Fix VMAT SCP MU scaling and clinical criteria logic

[sijiaww]

Summary

This PR includes a small set of fixes:

1. Fix MU scaling in the VMAT SCP intermediate optimization to match Eclipse MU.
2. Fix the clinical_criteria logic when checking and modifying criteria.

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Changes

1. VMAT SCP MU scaling fix

In portpy/photon/vmat_scp/vmat_scp_optimization.py:

Adjust the lower-bound constraint on the interior beamlet intensities from:

constraints += [int_v >= self.vmat_params['mu_min']]

to

constraints += [int_v * 100 >= self.vmat_params['mu_min']]

This aligns MU handling within the SCP intermediate optimization with Eclipse’s MU scaling.

2. Clinical criteria handling

Both modify_criterion() and check_criterion_exists() contained the same logical error:
they compared a constraint key (string) to the entire constraint dictionary, which always evaluated to false.

The updated logic now:

1. Properly matches criteria by type and parameters,
2. Iterates through the relevant constraint keys,
3. Updates only existing keys in the stored constraint dictionary,
4. Raises a clear warning if no matching criterion is found.

[gourav3017]

Changes approved